Four business partners began fighting. Two were stabbed. (Source: CBS 5 News)

PHOENIX (CBS5) -

A partner in a Phoenix Vietnamese restaurant has been arrested and booked into jail on two counts of second-degree murder after a fatal stabbing at the restaurant Thursday morning.

Two brothers died after they were stabbed, said Phoenix police Sgt. Tommy Thompson. He said the two were involved in a fight between two other business partners at shortly before 11 a.m. at Pho 35 Vietnamese Noodle House at 3515 W. Northern Ave.

Thompson said Tony Phung, 51, was arrested and suspected of stabbing the two victims.

Phung, his brother, Tim Phung, Timmy Hoang and his brother, Brandon Hoang, are co-owners of the restaurant.

Tony Phung said he and Brandon Hoang got into a disagreement over the hiring and firing of restaurant staff and the argument escalated after a couple hours, according to a court document.

Soon, all four were involved in a physical fight in the dining area and Tony Phung grabbed a knife and stabbed Timmy Hoang and then went after his brother, the document stated.

The Hoang brothers staggered out and collapsed just outside the front door, witnesses told police. Brandon Hoang was holding his brother when police and fire units arrived, according to the witnesses, who also said they didn't know who started the argument.

The Hoangs were taken to a hospital, where they died of their wounds.

Officers said they used a translator to aid in the investigation.

Stay with cbs5az.com and CBS 5 News for updates on this developing story.